• Title/Summary/Keyword: variance to mean ratio

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Simultaneous Tests with Combining Functions under Normality

  • Park, Hyo-Il
    • Communications for Statistical Applications and Methods
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    • v.22 no.6
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    • pp.639-646
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    • 2015
  • We propose simultaneous tests for mean and variance under the normality assumption. After formulating the null hypothesis and its alternative, we construct test statistics based on the individual p-values for the partial tests with combining functions and derive the null distributions for the combining functions. We then illustrate our procedure with industrial data and compare the efficiency among the combining functions with individual partial ones by obtaining empirical powers through a simulation study. A discussion then follows on the intersection-union test with a combining function and simultaneous confidence region as a simultaneous inference; in addition, we discuss weighted functions and applications to the statistical quality control. Finally we comment on nonparametric simultaneous tests.

Smile esthetics: Evaluation of long-term changes in the transverse dimension

  • Akyalcin, Sercan;Misner, Kenner;English, Jeryl D.;Alexander, Wick G.;Alexander, J. Moody;Gallerano, Ron
    • The korean journal of orthodontics
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    • v.47 no.2
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    • pp.100-107
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    • 2017
  • Objective: To analyze the long-term changes in maxillary arch widths and buccal corridor ratios in orthodontic patients treated with and without premolar extractions. Methods: The study included 53 patients who were divided into the extraction (n = 28) and nonextraction (n = 25) groups. These patients had complete orthodontic records from the pretreatment (T1), posttreatment (T2), and postretention (T3) periods. Their mean retention and postretention times were 4 years 2 months and 17 years 8 months, respectively. Dental models and smiling photographs from all three periods were digitized to compare the changes in three dental arch width measurements and three buccal corridor ratios over time between the extraction and nonextraction groups. Data were analyzed using analysis of variance tests. Post-hoc multiple comparisons were made using Bonferroni correction. Results: Soft-tissue extension during smiling increased with age in both groups. The maximum dental width to smile width ratio (MDW/SW) also showed a favorable increase with treatment in both groups (p < 0.05), and remained virtually stable at T3 (p > 0.05). According to the MDW/SW ratio, the mean difference in the buccal corridor space of the two groups was $2.4{\pm}0.2%$ at T3. Additionally, no significant group ${\times}$ time interaction was found for any of the buccal corridor ratios studied. Conclusions: Premolar extractions did not negatively affect transverse maxillary arch widths and buccal corridor ratios. The long-term outcome of orthodontic treatment was comparable between the study groups.

INFLUENCE OF HEATED SPREADER ON THE SEALING ABILITY OF LATERAL CONDENSATION (측방가압충전시 Heated Spreader 사용유무가 근관밀폐에 미치는 영향)

  • Chung, Won-Gyun;Hong, Chan-Ui
    • Restorative Dentistry and Endodontics
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    • v.24 no.1
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    • pp.222-232
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    • 1999
  • The purpose of this study was to evaluate the effect of heated spreader on the sealing ability of lateral condensation, compared with regular cold spreader. Forty two extracted human teeth with single canal were randomly placed into 3 experimental groups, and four additional teeth were used as positive and negative controls. Each group was prepared with Ni-Ti Profile #40 using step-down technique and obturated with standardized colored gutta-percha cone by standard(cold) lateral condensation technique, warm lateral condensation technique with Endotec and hot spreader soaked in glass bead sterilizer, each with Sealapex sealer. Control groups were not obturated, but prepared. After 2 days in 2% methylene blue, the teeth were invested and made into transparent resin blocks. And then, each block was sectioned horizontally with microtome at 1, 2, 3, 4, 5 mm levels from the apex. The linear extent of dye penetration was examined with stereomicroscope at ${\times}$20 magnification. At each of 5 levels, ratio of the area of gutta-percha was obtained by calculating the area of gutta-percha to the total area of the canal. The data collected were then analyzed statistically using an analysis of variance(ANOVA) and Scheffe test. The results were as follows ; 1. All experimental groups produced the apical microleakage. 2. The mean leakage was 1.57${\pm}$0.76mm for cold spreader group, 0.86${\pm}$0.95mm for Endotec spreader group, and 0.64${\pm}$0.93mm for hot spreader group. The difference between hot spreader group and cold spreader group was statistically significant(p<0.05). 1. At the 1 mm level, the mean ratio of area of gutta-percha was 74.58${\pm}$13.15(%) for cold spreader group, 65.42${\pm}$14.62(%) for Endotec spreader group, and 80.72${\pm}$14.63(%) for hot spreader group. There was statistically significant difference between hot spreader group and Endotec spreader group(p<0.05). 2. At the 2mm level, the mean ratio of area of gutta-percha was 87.86${\pm}$11.22(%) for cold spreader group, 66.55${\pm}$14.02(%) for Endotec spreader group, and 92.93${\pm}$7.24(%) for hot spreader group. There was statistically significant difference between Endotec spreader group and other two spreader groups(p<0.05). 3. At the level 3, 4, 5 mm, there was no statistically significant difference between each group. Within the limits of the results of this experiment, warm lateral condensation technique with hot spreader soaked in a glass bead sterilizer demonstrated favorable apical sealing effect and improved density of gutta-percha mass. Thus, it is thought that this obturation technique is effective for clinical use and beneficial to reduce condensation forces, also economical and easy. Lateral condensation, Heated spreader, canal sealing, Microleakage.

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Factors Influencing Sexual Satisfaction in Women who have had a Hysterectomy : A comparative group study (자궁적출술을 받은 부인과 자궁적출술을 받지 않은 부인의 성생활 만족 요인 분석)

  • 장순복
    • Journal of Korean Academy of Nursing
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    • v.20 no.3
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    • pp.357-367
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    • 1990
  • This descriptive study was done to identify factors influencing sexual satisfaction in women who had had a hysterectomy and to compare these with women who had not had a hysterectomy. The purpose was to contribute theoretical understanding on which to base nursing care planning. One group of subjects were 156 women who had had a hysterectomy, between one and 18 months post surgery, living with their spouse, having no complications, and menstruating before surgery. The other group of subjects were 282 healthy women who were living with their husbands and menstruating. The study tool consisted of 108 items including item concerning personal characteristics, characteristics related to the hysterectomy, husband's support, body image, emotions, attitude toward the sexual relationship, knowledge of sexuality, sexual behavior, and sexual satisfaction. Sexual satisfaction was measured by a tool based on Derogatis Sexual Function Inventory. The range of the internal level of the study tool was from. 5208 to .9462. Data collection was done during the period from June 20 to Aug.20, 1989. The same questionnaire was used of data collection for both groups, but a mail survey method was used for the women who had had a hysterectomy, and an interview method was used for the women who had not had a hysterectomy. Data analysis was done using frequency, ratio, mean and S.D. for the characterstics of the subjects and level of sexual satisfaction. t - test or ANOVA was used for the differences between the groups with regard to the general and hysterectomy related characteristics. The relationship between the score for sex life related factors and the level of sexual satisfaction was analyzed using the Pearson Correlation, and the influencing factors on sexual satisfaction were analyzed by stepwise multiple regression. The results of this study were as follows ; 1. Mean age and income level were the only general characteristics for the two groups that were significantly different. The mean age, and income level of the group who had had a hysterectomy were 45years, and 1,150,000 won respectively, and for those who had not had a hysterectomy, 41 years and 999,000 won. 2. There was no statistical difference of the sexual satisfaction score between the two groups. 3. There was differences in the factors influencing sexual satisfaction between the two groups. Factors influencing sexual satisfaction for the group who had had a hysterectomy were husband's support (R=.5793, P=.000) and the women's Knowledge of sexuality(R=.6670, P=.000) (total variance : 33.56). On the other hand, emotional status(R=.4294, P=.000), sexual behavior(R=.4294, P=.000), husband's support(R=.5274, P=.000) and attitude towards sexual relations (R=.5412, P=.000) (total variance : 54.12) were the factors influencing sexual satisfaction in the group who had not had a hysterectomy. Since husband's support and sexuality knowledge were identified as factors influencing sexual satisfaction of women who have had a hysterectomy, it can be concluded that, before a woman who has had a hysterectomy is discharged from hospital, nurses should include strategies in the nursing care plan that will promote husband's support and the women's knowledge of sexuality.

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Potential of the Quantitative Trait Loci Mapping Using Crossbred Population

  • Yang, Shulin;Zhu, Zhengmao;Li, Kui
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.12
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    • pp.1675-1683
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    • 2005
  • In the process of crossbreeding, the linkage disequilibria between the quantitative trait loci (QTL) and their linked markers were reduced gradually with increasing generations. To study the potential of QTL mapping using the crossbred population, we presented a mixed effect model that treated the mean allelic value of the different founder populations as the fixed effect and the allelic deviation from the population mean as random effect. It was assumed that there were fifty QTLs having effect on the trait variation, the population mean and variance were divided to each QTL in founder generation in our model. Only the additive effect was considered in this model for simulation. Six schemes (S1-S6) of crossbreeding were studied. The selection index was used to evaluate the synthetic breeding value of two traits of the individual in the scheme of S2, S4 and S6, and the individuals with high selection index were chosen as the parents of the next generation. Random selection was used in the scheme of S1, S3 and S5. In this study, we premised a QTL explained 40% of the genetic variance was located in a region of 20 cM by the linkage analysis previously. The log likelihood ratio (log LR) was calculated to determine the presence of a QTL at the particular chromosomal position in each of the generations from the fourth to twentieth. The profiles of log LR and the number of the highest log LR located in the region of 5, 10 and 20 cM were compared between different generations and schemes. The profiles and the correct number reduced gradually with the generations increasing in the schemes of S2, S4 and S6, but both of them increased in the schemes of S1, S3 and S5. From the results, we concluded that the crossbreeding population undergoing random selection was suitable for improving the resolution of QTL mapping. Even experiencing index selection, there was still enough variation existing within the crossbred population before the fourteenth generation that could be used to refine the location of QTL in the chromosome region.

The Demersal Fishes of Asan Bay -I. Optimal Sample Size- (아산만 저어류 I. 적정 채집 방법)

  • LEE Tae-Won
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.24 no.4
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    • pp.248-254
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    • 1991
  • The demersal fishes of Asan Bay were collected by an otter trawl in August 1990 to determine optimum sample size for the analysis of community structure. A total of 17 species comprising 957 individuals and 21,840 grams in biomass was collected. Predominant species were Cynoglossus joyneri, Thrissa koreana, Hexagrammos otakii and Johnius belengerii. Coefficients of variation for fish numbers in ten replicate tows ranged from 2.2 to $385.1\%$ for four abundant species and from 52.2 to $162.0\%$ when all species were considered. The cumulative number of species increased rapidly until 4 hauls, and less than 1 species per haul in average was added thereafter. The cumulative diversity index reached nearly an asymptote value when three of samples were combined. Variance in the number of individuals diminished as the sample size increased. The ratio of variance to mean numbers (dispersion index) was not significantly different from the unity when first 4-haul samples were combined. Four of 20-minute trawl haul are proposed to be a proper sampling size for the unbiased estimation of abundance in the study area.

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Study on the fatty acid profile of phospholipid and neutral lipid in Hanwoo beef and their relationship to genetic variation

  • Beak, Seok-Hyeon;Lee, Yoonseok;Lee, Eun Bi;Kim, Kyoung Hoon;Kim, Jong Geun;Bok, Jin Duck;Kang, Sang-Kee
    • Journal of Animal Science and Technology
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    • v.61 no.2
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    • pp.69-76
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    • 2019
  • Maize which has very high omega-6 fatty acid content has been used as a main feed grain for Hanwoo beef production to increase marbling, and thus omega-6 to omega-3 fatty acids ratio in Hanwoo beef is expected to be biased. To elucidate the current status of omega fatty acids ratio in Hanwoo beef, fatty acid profiles of neutral lipid and phospholipid fraction were analyzed separately using 55 Hanwoo steers' longissimus dorsi muscle slaughtered at Pyeongchang, Korea from Oct. to Nov. 2015. In addition, an association study was conducted to evaluate associations between single nucleotide polymorphism (SNP) markers from references and omega fatty acid profiles in phospholipid of Hanwoo beef samples using analysis of variance (ANOVA). In neutral lipid fraction, composition of saturated and monounsaturated fatty acids was higher and polyunsaturated fatty acids was lower compared to those in phospholipid fraction. The mean n-6/n-3 ratios of Hanwoo were $56.059{\pm}16.180$ and $26.811{\pm}6.668$ in phospholipid and neutral lipid, respectively. There were three SNPs showing statistically significant associations with omega fatty acid content. GA type of rs41919985 in fatty acid synthase (FASN) was significantly associated with the highest amount of C20:5 n-3 (p = 0.031). CC type of rs41729173 in fatty acid-binding protein 4 (FABP4) was significantly associated with the lowest amount of C22:2n-6 (p = 0.047). AG type of rs42187261 in FADS1 was significantly linked to the lowest concentration of C20:4 n-6 (p = 0.044). The total n-6/n-3 ratio of the steer which has all four SNP types in above loci (27.905) was much lower than the mean value of the total n-6/n-3 ratio in phospholipid of the 55 Hanwoo steers ($56.059{\pm}16.180$). It was found that phospholipid and neutral lipid of Hanwoo have very high n-6/n-3 ratios compared to the reported data from different cow breeds. Four SNPs in genes related with fatty acid metabolism showed significant associations with the fatty acid profile of phospholipid and may have potential as SNP markers to select Hanwoo steers in terms of n-6/n-3 balance in the future.

A New Method on the Nonlinear Distortion Analysis in the OFDM Communication System (OFDM 통신 시스템에서 비선형 왜곡분석의 새로운 분석기법)

  • 이동훈;정기호;유흥균
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.6
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    • pp.538-545
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    • 2002
  • In the orthogonal frequency division multiplexing (OFDM) system, the nonlinear distortion in the high power amplifier(HPA) degrades the system performance because of the high peak-to-average power ratio (PAPR). In this paper, a semi-analytical method is newly proposed for the performance evaluation of the nonlinearly distorted OFDM communication system. In the proposed method, at first, the probability density function (pdf) of the PAPR is generated by computer simulation. Then, mean and variance of the non-linear distortion noise process are computed. Next, the overall BER is found by the analytical method. When the equivalent SSPA model is applied in case of the QPSK/16-QAM and AWGN channel, the BER is calculated for the variation of the IBO(input back-off) and PAPR parameter. It is shown that the results by proposed method are very similar to those of the conventional Monte-Carlo method. The computation time can be considerably reduced than the conventional method that depends on the magnitudes of BER and IBO.

Effects of Nasal Continuous Positive Airway Pressure Application on Sympathetic Activation : Power Spectrum Analysis of Electrocardiogram in Obstructive Sleep Apnea Syndrome (폐쇄성 수면무호흡증에서 지속적 상기도 양압술 시행이 교감신경계 활성도에 끼치는 영향 : 심전도 스펙트럼 분석)

  • Youn, Tak;Park, Hae-Jeong;Kim, Eui-Joong;Jeong, Do-Un
    • Sleep Medicine and Psychophysiology
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    • v.7 no.1
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    • pp.43-50
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    • 2000
  • Objectives: Obstructive sleep apnea syndrome(OSAS) is known to be associated with the changes of autonomic nervous system (ANS). Nasal continuous positive airway pressure(nCPAP) treatment was found to correct abnormal ANS changes in OSAS but it remains to be further clarified. We aimed to assess the effects of nCPAP on ANS manifested on electrocardiogram, using spectrum analysis in the subjects with OSAS. Methods: Digital polysomnography was performed in 18 patients with OSAS(mean age $43.7{\pm}16.6$ years ; 17 males, 1 female ; mean respiratory disturbance index (RDI) $48.6{\pm}20.9$) for one baseline and another CPAP nights. From each night, 300 continuous beats of ECGs without artifact were chosen from both stage 2 sleep and REM sleep and they were used for power spectrum analysis. We compared between baseline and CPAP nights the heart rate variability including VLF(very low frequency power), LF (low frequency power), HF(high frequency power), R-R means, R-R variance, and LF/HF ratio, using Wilcoxon signed ranks test. Results: In all patients, nCPAP proved to be effective in relieving apneas and snoring. During nCPAP night compared with baseline night, decreases in VLF(p<0.05), LF(p<0.01), and R-R variance(p<0.05) were found in stage 2 sleep, and decreased LF(p<0.05) was found in REM sleep. No significant differences in each sleep stage were found in other variables between the two nights. Conclusion: Our findings suggest that OSAS increases the activity of sympathetic nervous system and nCPAP application effectively decreases the activity. And nCPAP does not appear to influence the parasympathetic nervous activity in OSAS.

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Genetic Analysis by Diallel Crosses in F1 Generation of Silkworm, Bombyx mori (이면교잡에 의한 가잠 F1세대의 몇 가지 양적 형질에 관한 유전 분석)

  • 정원복;장권열
    • Journal of Sericultural and Entomological Science
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    • v.28 no.1
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    • pp.24-29
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    • 1986
  • A set of 21 crosses of F1 generation by diallel crosses from seven parent silkworm, Bombyx mori L. were used as materials to estimate genetic parameters such as gene action and combining ability. Experiments were conducted in 1985, and three characters, which are weight of cocoon, weight of cocoon layer and ration of cocoon layer, were observed. The data were analyzed for each character by Jinks', Hayman's and Griffing's methods. The result obtained are summarized as follows : 1. In Vr-Wr graphical analyses, weight of cocoon was found to be inherited in over dominance, and weight of cocoon layer and ration of cocoon layer were observed as partial dominance. 2. Estimate of additive component of variance(D) was greater than those of dominance component of variance(H) for weight of cocoon layer and ratio of cocoon layer, and positive values of F were observed for all characters. 3. Mean squares of general combining ability were higher than those of specific combining ability. 4. Variety Jam 107 was expressed as the highest GCA effects for three characters, and high SCA effects for all characters were observed in combinations of 113 $\times$Jung 14 and Jam 107 $\times$Jung 14.

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